A 12-year study of two measles-containing vaccines, performed by the Kaiser Permanente Vaccine Study Center in Oakland, Calif., found that seven main adverse outcomes were unlikely after either vaccine.
A total of 123,200 measles-mumps-rubella varicella vaccines and 584,987 measles-mumps-rubella and varicella vaccines were administered to children aged 12-23 months from January 2000 to June 2012 and evaluated. After comparing MMRV with MMR+V, researchers reported increased risk of seven main neurological, blood or immune system disorders was not associated with the vaccines, and most of the outcomes studied were unlikely following the administration of either vaccine.
"This study did not identify any new safety concerns comparing MMRV with MMR+V or after either the MMRV or the MMR+V vaccine," Nicola P. Klein, MD, PhD, co-director of the Vaccine Study Center and lead author of the study, said in a statement. "In fact, there were few or zero events for several outcomes following vaccination. These findings indicate that even if an increased risk for these outcomes exists, the risk is low and rare. This should reassure parents that these outcomes are unlikely after either vaccine."
Additionally, researchers concluded that the findings from previous studies of the same two vaccines are associated with a small risk of fever and febrile seizure among 1-year-old children between seven to 10 days after administration.